HEREDITY AND ENVIRONMENT
[To the Editor of the SPECTATOR.] Sin,—Mr. Joad's seventh conclusion is as follows :—" That nevertheless eugenics in the sense of the purposive breeding of desired types is for all practical purposes impossible, owing to the haphazard selection of those genes which go to form any particular offspring." As eugenics is much too serious a matter to be dismissed in the last paragraph of a " popular "'" article on a disputed scientific question, I shall be obliged you will allow me space for a short comment on this remarkable
statement. 1.
Among domesticated animals and plants " purposive breeding of desired types " has been universally and success- fully carried out, and is still being carried out ; for example, pedigree cows have been bred to give over 3,000 gallons in the year, pedigree pullets to lay over 300 eggs in the year and pedigree wheat to combine baking quality with yield. And though I do not know whether the American-bred offspring of Russian Jews are Russians, Americans or Jews (one might perhaps hazard a guess about the last category !), yet it is fairly obvious that Argentine farmers would not pay thousands of pounds for English pedigree Shorthorn bulls it their type were lost in their Argentine offspring.
In the case of human beings we may take the very instance of red hair which Mr. Joad has himself given. So far is the haphazard selection of genes from being in this case an insuper- able obstacle to the purposive breeding of a desired type that a millionaire with a taste for colour could quite easily establish a red-headed sub-race by the simple process of providing free housing in a privately built suburb on condition that all parents inhabiting the houses were red-headed. As black or brown haired offspring are almost if not quite unknown when both parents have red hair, the required type would to all intents and purposes be established at once and would be-
maintained as long as the inhabitants of the suburb interbred.
Turning to more serious matters, many of those who have given most thought to the subject are of the opinion that lack of resistance to tubercle bacillus is inherited in much the same way as is red hair, though admittedly the evidence is neces- sarily less obvious. This being so would Mr. Joad take the risk of encouraging his daughter to marry a man both of whose parents had died of consumption ? And, if not, would he not be practising the purposive breeding of the desired tubercle
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